syzbot

==================================================================
BUG: KCSAN: data-race in fasync_remove_entry / sock_wake_async

write to 0xffff888128cfa9d8 of 8 bytes by task 18120 on cpu 0:
 fasync_remove_entry+0xb7/0x120 fs/fcntl.c:882
 fasync_helper+0xc9/0xd6 fs/fcntl.c:981
 sock_fasync+0x74/0x100 net/socket.c:1308
 __fput+0x448/0x4f0 fs/file_table.c:277
 ____fput+0x1b/0x30 fs/file_table.c:313
 task_work_run+0xf5/0x130 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop+0x2ae/0x2c0 arch/x86/entry/common.c:164
 prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:278 [inline]
 do_syscall_64+0x36e/0x390 arch/x86/entry/common.c:304
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff888128cfa9d8 of 8 bytes by task 18117 on cpu 1:
 sock_wake_async+0x37/0x100 net/socket.c:1323
 sk_wake_async include/net/sock.h:2200 [inline]
 sk_wake_async include/net/sock.h:2196 [inline]
 unix_release_sock+0x5d2/0x670 net/unix/af_unix.c:553
 unix_release+0x3a/0x60 net/unix/af_unix.c:862
 __sock_release+0x85/0x160 net/socket.c:605
 sock_close+0x1f/0x30 net/socket.c:1283
 __fput+0x1c3/0x4f0 fs/file_table.c:280
 ____fput+0x1b/0x30 fs/file_table.c:313
 task_work_run+0xf5/0x130 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop+0x2ae/0x2c0 arch/x86/entry/common.c:164
 prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:278 [inline]
 do_syscall_64+0x36e/0x390 arch/x86/entry/common.c:304
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 18117 Comm: syz-executor.0 Not tainted 5.6.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================